Snow biking. Could be fun. Grab a bike and hurtle down a snowy mountain sliding excitingly at high speeds.
Why would this be classed as a silly sport? It's quite simple. These people don't bike downhill. They ride on normal flat land or even uphill in thick snow. This, for them is fun ???!

Well then Icebiking has been around a long time. The concept dates virtually from the invention of the bicycle.

The bicycle was used by people from all walks of life in every country such was its ease of use. Hardy cyclists rode their bikes into wilderness areas where there where no roads. The invention of the bicycle lead to the demand for roads and is responsible for today's modern road system. All this happened before the automobile was available to any but the rich.

It seemed inevitable that the bike would be a good idea for winter transport The freedom of movement meant it would not easily be affected by autumn breezes or winter chills. It was certainly better than walking.

Ice biking is a popular sporting event with races held practically every week. Racing (round a figure of eight track or long distance) is the most popular. Mind you I cant really think of anything else that you could do.

If you fancied giving it a go - Ice bikes can be made just from taking a normal bike and making a few adjustments.

Mountain bikes are by far the most popular types of snow bikes. You would need dirt, water, and snow flaps.
A rack to carry stuff.
Big fat MTB tires.
BMX style pedals with PowerGrips.
Lights.
A sturdy frame and durable components.
A well lubricated chain.

So there you go. With a few careful adjustments you too can have an Icebike. Unfortunately this activity/sport is mainly used in USA and Canada due to the amount of snowfall they receive. So if you did want to join the sport you would have to get in touch with an icebiking association.
Check outhttp://enteract.com/~icebike/ for details.